Hillier was unable to take trees out of the frozen ground for a week. Container production manager Dave Hooker said there was enough glasshouse space to put plants under cover "but we've used more fuel then we'd like to".
Seiont owner Neil Alcock said heating costs had quadrupled over the past 10 days at his North Wales nursery. Alcock said he had put vulnerable stock under his 0.4ha of glass.
He added: "Nothing has been made unsaleable. It's a good test for new varieties from South Africa and Australia."
Bressingham Gardens director Adrian Bloom said: "Tender plants may have suffered. But, to some extent, getting a proper winter is a good thing to clean up pests and diseases." He said phormiums in protected positions "have not turned a hair this year" but he has covered their bases with straw and fleeced the top.
Supplier Harrod Horticultural said that "almost all orders" received have included fleece since Christmas.
ADAS consultant Andrew Hewson said fuel bills were a concern for protected ornamentals. He said broadleaved evergreens had rootballs frozen and wind burnt leaves, while lavender and Choisya were also vulnerable.
Hewson recommended using fleece as protection, taking it off during the day to let plants breathe. He said growers should have planned space in tunnels. www.HorticultureWeek.co.uk/forums to comment on this story.